What is the Harmful Effect of Heat & Who is at Most Risk? Solved

As global temperatures rise, understanding the harmful effect of heat is more important than ever. Prolonged exposure to extreme heat can lead to serious health risks, environmental damage, and economic strain. 

In this blog post, we will explore how does extreme heat affect human health, the environment, and daily life, and some necessary preventative methods.

What is the effect of heat in the body?

Extreme Heat Statistics

A heatwave is a period during which local excess heat builds over a number of exceptionally hot days and nights. 

Even worse, climate change increases the frequency, length, severity, and size of heatwaves and prolonged periods of extreme heat.

According to the US National Centers for Environmental Information's (NCEI) most recent Global Climate Report, July 2024 was the hottest month since global records started in 1850. 

Also, it marked the 14th consecutive month in which the temperature record was broken.

Extreme heat and climate change

According to one study, from 2018 to 2022, individuals suffered health-threatening heat for an average of 86 days per year. 

Human-caused climate change increased the likelihood of 60% of such temperatures by more than double.

In fact, extreme heat may have devastating health consequences. For example, heatwaves in Europe during the summer of 2022 killed almost 60,000 people. 

In 2021, experts analyzed data from 732 sites in 43 countries and estimated that climate change was responsible for 37% of heat-related fatalities between 1991 and 2018.

Below are some recent heat waves and their consequences:

• Canada (June 2021): British Columbia endured six consecutive days of extreme heat, leading to over 600 deaths and an estimated $12 million in healthcare-related expenses.

• Italy (July 2022): As wildfires erupted across the country, Italy issued its highest-level heatwave alert. That summer, it recorded one of the highest heat-related death rates in Europe.

The heat wave in Italy in 2022

• Iran (August 2023): In response to dangerously high temperatures, the government shut down all public offices, banks, and schools for two days to protect public health and ease pressure on the power grid.

• India (June 2024): One of the country’s longest-lasting heat waves resulted in over 40,000 suspected heat stroke cases and at least 100 reported deaths.

Harmful Effect of Heat on Health

As climate change raises temperatures, understanding the health impacts of extreme heat is more important than ever. The following are ways heat affects health.

Mortality & morbidity rates

Prolonged exposure to high temperatures can lead to heat exhaustion, heatstroke, and heat cramps. Vulnerable groups like the elderly, children, and people with chronic illnesses face the highest risks.

Moreover, during major heat waves, hospitals often see a rise in emergency visits. In severe cases, heat-related illnesses can rapidly become life-threatening, contributing to a sharp increase in heat-related deaths.

Extreme heat significantly impacts public health

Dehydration

The human body comprises almost 60% water, while brain tissue has over 85%. 

In the summertime, as the temperature rises and the body attempts to cool itself by sweating, dehydration can result, particularly in youngsters.

Although fluid loss happens during strenuous physical activity, even basic actions such as gardening, walking, or bicycling can result in a significant loss of fluid quickly.

Heart health

As the body heats up, it increases stress on the cardiovascular system. This happens because more blood is directed to the skin to help release heat, leaving less available for circulation back to the heart. 

As a result, the heart must work harder to maintain blood flow throughout the body. 

According to Stephen Cheung, a senior research fellow at Brock University, this added strain can reduce the heart’s oxygen and nutrient supply, potentially leading to life-threatening conditions such as a heart attack.

The harmful effect of heat on our heart

Mental health

Extreme heat doesn’t just affect the body—it can also take a serious toll on mental health. 

High temperatures have been linked to increased stress, irritability, anxiety, and difficulty sleeping. Prolonged heat can worsen symptoms for people with existing mental health conditions such as depression or schizophrenia.

"Extreme heat may make people more irritable or depressed, it can cause psychotic outbreaks, and people taking certain psychiatric medications are more susceptible to heat," said Jane Gilbert, the world's first Chief Heat Officer.

Physical activity

High temperatures can significantly reduce the body’s ability to perform physical activity safely. 

During extreme heat, the body works harder to stay cool, leading to faster fatigue, dehydration, and a higher risk of heat-related illnesses like heat cramps, heat exhaustion, or heatstroke. 

Outdoor workers, athletes, and those exercising in hot conditions are especially vulnerable. In severe cases, physical exertion in extreme heat can become life-threatening.

Heat waves influence physical activities

Who is Most at Risk of Heat-related Health Problems?

Although everyone is vulnerable to the health impacts of extreme heat, certain groups are at significantly more risk than others. 

According to the Environmental Protection Agency (EPA), infants and children are especially susceptible since they lose fluid faster than adults and must rely on caregivers to keep them cool.

Pregnancy can also increase vulnerability to heat-related issues since the body must work harder to cool the pregnant woman and the fetus. 

Extreme heat has been linked to adverse pregnancy outcomes such as stillbirth and low birth weight.

Pregnant people are vulnerable to hot weather

Older adults are more likely to have health issues such as diabetes, which puts them at greater risk. They have a different response to heat than younger people.

Furthermore, research has demonstrated that heat waves pose a greater risk to those with cardiovascular or respiratory problems. Specific medications may further increase a person's chance of suffering poor health consequences in excessive heat.

How to Prevent the Harmful Effect of Heat?

Preventing heat-related health issues starts with awareness and preparation. By taking simple precautions, you can reduce your risk of heat-related illnesses, especially during extreme temperatures.

Below are a few key prevention tips:

Tips to minimize the health effects of heat

• Stay hydrated by drinking plenty of water throughout the day

• Avoid outdoor activities during peak heat hours

• Wear lightweight, breathable clothing

• Use fans or air conditioning to stay cool indoors

• Check on vulnerable individuals, such as the elderly or young children

For more detailed guidance, be sure to read our full guide on hot weather safety tips.

Conclusion

The harmful effect of heat goes far beyond discomfort; they can seriously impact both physical and mental health, leading to increased illness, hospitalizations, and even death. Therefore, staying informed and taking preventive measures is essential to protect ourselves and those most vulnerable in extreme heat conditions.